1Preheat the oven to 375°F. Oil a 3-quart baking dish.
2In a large pot of boiling, salted water, cook the pasta to al dente according to package directions. Drain and set aside.
3In a large, deep frying pan over medium-high heat, cook the sausage until browned and cooked through, about 10 minutes. Transfer to a cutting board; when cool enough to handle, cut the sausage into slices. Discard all but 1 tablespoon fat from the frying pan. Add 1 tablespoon olive oil and the peppers and onion to the pan. Sprinkle with salt and cook, stirring, until tender and browned. Scrape into a large mixing bowl and add the sausage. Add the marinara sauce and stir to combine. Add the pasta and half the Parmesan to the bowl and toss the entire mixture together.
4Add half of the pasta mixture to the prepared baking dish. Dollop evenly with half of the ricotta, then sprinkle with half of the Parmesan and half of the mozzarella. Top with the remaining pasta mixture in an even layer, then top with the remaining ricotta and mozzarella.
5Bake until warmed through and bubbly and the cheese is melted, about 1 hour. Let rest for 5 minutes then serve.
Significantly lower in carbs and calories than traditional pasta, spaghetti squash serves as a healthier weeknight dinner base. You won't believe how easy it is to cook. Prep-ahead to make dinners and lunches easier and faster throughout the week.
Spaghetti squash is a great lower-calorie, lower-carb alternative to pasta. It makes the perfect comfort food or salad starter, and is a neutral-tasting veggie that absorbs all the flavors of this simple dish.